FAQ

Aerosols

Q.How do I properly dispose of an aerosol can after it is empty?

It may be different state-by-state, so contact your state environmental agency for regional specific regulations. For a general guideline, here is the process according to EPA hazardous waste regulations 40CFR. The can has to be brought to or approach atmospheric pressure to render the can empty. Puncturing is not required, only that it “approach atmospheric pressure”, i.e. empty the can contents until it’s no longer pressurized. This insures that as much contents as is reasonably possible are out of the can. It is then considered “RCRA-empty”. At that point it can be handled as any other waste metal container, generally as scrap metal under the recycling rules. Note that the can is still considered a solid waste at this point (not necessarily hazardous waste).

Board Repair Pens

Q.What is the useable temp operating range of the TraceTech Conductive Pen (2505-N)?

From -55° C to 150° C.

Conformal Coating

Q.What spigot or spout do you recommend for your metal 5-gallon and 55-gallon drums?

Both of Techspray's metal 5-gallon and 55-gallon drums are compatible with standard 3/4" and 2" spouts. Ideally use 3/4" for 5-gallon, 2" for 55-gallon.

Q.What types of coverage areas are to be expected with the conformal coatings in general?

Wet film thickness

Sq. ft. per gal.

0.1 mil

16,040

0.5 mil

3,210

1 mil

1,600

2 mil

802

3 mil

535

4 mil

401

5 mil

321

6 mil

267

7 mil

229

8 mil

201

9 mil

178

10 mil

160

Q.The "stock" products are too viscous for some applications. Are there other viscosity ranges offered or could the original product be diluted to the appropriate range?

We offer "thinner" viscosity ranges as custom blends. However, each of the 3 types of coatings in bulk may be thinned with 2105.

Q.When using conformal coatings in general, what causes a "milky" cure or white "foam" on the substrate?

In almost all cases, the cloudy or milky cure comes from coating in higher humidity conditions. The white foam (from an aerosol) is caused the same way. We have the following suggestions:

If possible, allow the substrate and coating material to come to approximately the same temperature when applying.

Avoid applications in RH > 60%. High humidity ranges will discolor some coating resins and will start curing others. Besides the aesthetic value, it certainly may affect adhesion to the material.

Specifically on the silicone coating, if the resulting application is foamy, increase the focal point of the can, ie back off to about 10 -12” from the substrate & make 2 -3 light passes rather than one heavy pass to coat the board.

Cleaning Solvents

Q.Does Techspray have any products that meet MIL-C-81302 CL2 TY2A?

MIL-C 81302 is a specific requirement for Freon-based cleaners (trichloro-trifluoroethane), so in effect is an outdated spec except where use is allowed. It does not apply to any current Techspray products.MIL-PRF-29608 is a more current spec for solvent performance requirements. "Cleaning and Cleaning-lubricating compounds, Electrical Contact, Low Ozone Depletion Potential" is the name of the spec.The following G3 cleaners are Type II, Class C under MIL-PRF-29608:

G3 Blue Shower (1630-16S)

G3 Flux Remover (1631-16S)

G3 No-Clean Flux Remover (1634-16S)

G3 Contact Cleaner (1632-16S)

G3 Universal Cleaner (1638-G)

Precision-V Cleaner (1651-16S and 1651-G)

The “type” is referred to in the older version. It is no longer used in the newer version. Both are performance specifications. The above products meet these requirements.

Q.There are a number of regulations prohibiting the use of chlorinated solvents. Should I be concerned with Trans, which is used in your non-flammable cleaners like G3 and Precision-V.

No, it should not be a concern. Many of Techspray's non-flammable solvents (e.g. G3, Precision-V) contain 1,2-trans-dichloroethylene (Trans, CAS# 156-60-5), which has caused confusion. The regulations controlling chlorinated solvents do not generally pertain to Trans. The following are the reasons:

Many are confused with “chloro” substances due to the NESHAP requirements. The big 3 chlorinated substances are Perchloroethylene (Perc), Trichloroethylene (TCE), and methylene chloride. The association of those with all chlorinated substances is not valid.

NESHAP requirements only refer to restrictions of emissions of hazardous air pollutants (HAP). Of the nearly 200 substances listed as HAP’s, Trans is not on that list. Reference the following link: http://scorecard.goodguide.com/chemical-groups/one-list.tcl?short_list_name=hap.

Trans has the same exposure limit (per ACGIH) time-weighted average (TWA) as 2-propanol (IPA) -- 200 ppm. In contrast, n-Propyl Bromide (nPB) is commonly used in vapor degreasers, with TWA established by ACGIH of 10 ppm. It has been proposed to be reduced to 0.1 ppm. nPB is also listed on various carcinogen lists, notably Prop 65.

Desoldering Braid (Wick)

Q.How are Techspray's desoldering braid products classified?

Techspray uses 2 types of flux: Prowick line is a natural gum rosin. Per J-STD-004 Section 3.2, the Prowick is classified as ROL0. Per British Std. EN 29454-1:1993 and ISO9454-1:1990, Prowick has a classification of 1.1.1.B.No Clean flux is a synthetic (non-colophony)flux. Per J-STD-004 Section 3.2, it is classified as REL0. Per British Std. EN 29454-1:1993 and ISO9454-1:1990, the No Clean flux has a classification of 1.2.3.B.

Duster

Q.I have experienced the duster can frosting over and also frost occurring on the cleaned substrate. What causes this and will it harm the substrate?

This phenomenon occurs due to the expansion of the compressed refrigerant liquid as it dispenses through the aerosol valve and flashes to a gas. If the aerosol is operated for a long period, frost may form on the can because it is freezing the surrounding water vapor from the air.If it is collecting on the material to be cleaned, the operator is dispensing for too long of a period or is dispensing it too close to the material. The frost will evaporate and leave no residue. However, particulate matter blown onto a sensitive surface may cause damage due to the high pressure of the duster if dispensed too closely to that surface.

Heat Sink

Q.What is the lowest operable point of 1978?

At -65° F, the product will continue to sink away any generated heat. However, the binder component will solidify below the stated operational low of -40° F. As the material warms back up, the binder will soften again with no performance loss. This product has been used in the aerospace industry for over 30 years without any reported failures.

Try adding VMP naptha (a common paint thinner) to the compound at approx 1 part VMP to 100 parts compound. Mix thoroughly to get it back to the consistency required. This is mostly by “eyeball” so you may need a little less or a little more, depending on how dry the material is.

Q.What is the melting point of 1978?

Since the material is a paste, it has no true melting point because the binder component is already a liquid. However, some phase separation may be noted starting at ~ 250° F. although it is negligible.

Q.What is the thermal conductivity of Techspray heat sink?

Licron Crystal

Q.How long will the coating last before I have to reapply?

The EDS-safe properties don’t fade over time. The only thing they have to worry about is wear-and-tear on the surface. If a walking surface, I would recommend a floor coating instead. If a working surface, I would suggest putting and ESD-safe mat over the Licron Crystal coated surface. Licron Crystal is not chemically resistant, so the mat becomes very important if we are cleaning with a solvent like IPA and dripping it all over the place.If it is a surface out of reach, so it doesn’t get abused, I would recommend they check the resistivity every month, if it is critical, or every 3 months if less critical. If the resistivity hasn’t changed, they can leave it alone. How often they will have to reapply depends on the environment. If a clean environment, they can wipe down with water and make it last for a very long time – years even. If in a greasy, sooty environment, they will have to clean with some kind of cleaning agent, which can degrade the coating. This will require more frequent reapplication.

Temporary Solder Mask

Q.What could cause foaming problems during rinse-off of the water- soluble masks?

Particulates + surfactants during rinse = foam. Check filtration system or drain & recharge the rinse water system as necessary. The particulates may come from various sources, but excess solder flux being rinsed off the boards is a prime culprit. Bacteria in the water can cause foaming. Have a water sample analyzed.

We have tested all our masks at temperatures of 316° C (600° F) for 3 minutes exposure with no degradation.

Water-Based Cleaners

Q.Does DF-1 Defoamer (1555) cause a problem with conformal coating?

Techspray has performed extensive testing, and DF-1 Defoamer did not cause dewetting or loss of coating adhesion.Keep in mind that removal of any chemistry from the substrates is a function of rinse cycle pressure, volume, temperature, filtration, and other process parameters which vary by equipment and specific facility.Techspray would be happy to do the following for our customers:

If feasible, test customers’ boards using the DF-1 in our TechLab setting and return for subsequent coating and evaluation in the remainder of their process

A Techspray representative can be available for on-site evaluation of the product in the customer’s cleaning/coating process.